Human Rights Campaign, a national gay rights group, is using the color red to promote support for gay marriage, urging people who agree to wear the color and use it online.

The action comes as the Supreme Court considers arguments over the legality of same-sex marriage this week.

"Red symbolizes love. That's what marriage is all about," said Charlie Joughin, a spokesman for Human Rights Campaign. "It's incredible the people who are making a statement supporting love."

The group's logo, which is usually a yellow "equals" sign on a blue background, has been changed to a pink sign on a red background. The change happened Tuesday, the day the Supreme Court heard arguments in the first of two gay marriage cases.

Human Rights Campaign encouraged its more than 1 million Facebook fans to wear red and to use the red logo as their social media profile picture. By Tuesday evening, the post had more than 14,000 likes and 50,000 shares.

George Takei, famous for his role on Star Trek, was among people who changed their profile pictures to Human Rights Campaign's new red logo. Others included Lance Bass, a member of boy band *NSYNC, Maryland Gov. Martin O'Malley, a Democrat, and Florida Rep. Debbie Wasserman Schultz, chairwoman of the Democratic National Committee.

By Tuesday afternoon, the list of supporters continued to grow. Several public figures joined the efforts included Padma Lakshmi, Ill. Gov. Pat Quinn, a Democrat, and Democratic Sen. Mark Warner of Virginia.

Some businesses also joined the effort. Groupon, a daily deals website, posted a video of dozens of employees wearing red shirts. Absolut Vodka tweeted its support with a photo of a bottle wrapped in red fabric.

"We've got folks all across America using this as a visible and public way to show support for marriage equality," Joughlin said.